Optimization Of Energy Efficiency And Quality Parameters Of Cement Rotary Kiln Based On Numerical Simulation

The cement industry is one of the most important basic industries in our country,and the cement rotary kiln is one of the most important equipment in cement production,which has a significant impact on the energy consumption of cement production and the quality of cement products.A cement rotary kiln with appropriate parameters setting can not only greatly improve the energy efficiency,but also improve the firing quality of cement materials and prolong the life of the kiln.Because the cement rotary kiln is an extremely complex firing system,its energy efficiency optimization is complex,difficult and timeconsuming,especially when multi-objective optimization is performed on it,there will be problems such as difficulty in collecting data and large amount of calculation.Based on the background of our country’s two-carbon strategy,how to quickly and effectively improve the energy efficiency of cement rotary kilns while taking into account the quality of cement products has become a key issue for the cement industry to achieve technological green innovation and industrial green upgrades.Aiming at the difficulty of optimizing the energy efficiency of cement rotary kiln,this thesis takes the cement rotary kiln of a cement manufacturing enterprise in South China as the research object,and proposes an intelligent parameter optimization method based on numerical simulation technology.Firstly,this thesis establishes the index evaluation model of energy efficiency and quality of the rotary kiln,and then the numerical simulation model of the basic working condition of the rotary kiln based on Fluent is constructed.The data-driven model of energy efficiency and quality of rotary kiln based on Generalized Regression Neural Network（GRNN）combined with Nondominated Sorting Genetic Algorithm-III（NSGA-III）multi-objective optimization algorithm to solve the optimal process parameter combination of the research object.The main contents are as follows:1.Aiming at the problem that the energy efficiency and temperature field quality of the rotary kiln are difficult to evaluate,through in-depth understanding of the working characteristics and working mechanism of the rotary kiln,and analyzing its heat transfer mode,a quantitative index model of energy efficiency and quality is constructed.Based on the heat balance,this thesis analyzes the income and expenditure of materials and heat in the rotary kiln system,and then constructs the thermal efficiency of the rotary kiln as the energy efficiency index.Combined with previous research and enterprise research,it is determined to take the maximum firing temperature and the length of the firing zone of the rotary kiln as the quality index.2.Aiming at the problems of difficult data collection,long time-consuming and high experimental cost,this thesis constructs the numerical simulation model of cement rotary kiln based on Fluent,which is used as the data support of this paper.In this thesis,the CFD model is constructed by combining the physical structure and working characteristics of the rotary kiln.The flow field information under the working condition is obtained by inputting the boundary conditions of the basic working condition.The reliability of the numerical simulation model is verified by comparing the change trend of the flow field and the relative error with the real value.3.Aiming at the problem that many process parameters of rotary kiln lead to difficult optimization,based on the analysis of variance,this thesis collects data through the orthogonal experimental table and numerical simulation model,analyzes the significance of the impact of each process parameter on the energy efficiency and quality index of cement rotary kiln,eliminates the parameters with small impact,and retains the parameters with large impact as the process parameters to be optimized.This thesis determines the secondary air speed,the secondary air temperature and the coal input as the process parameters to be optimized,and further analyzes the single factor influence law of the process parameters to be optimized on the energy efficiency and quality of the rotary kiln,so as to provide parameter adjustment guidance for enterprises.4.Aiming at the problems that numerical simulation is time-consuming and difficult to combine with intelligent optimization algorithms,this thesis studies the rotary kiln with energy efficiency and quality as the optimization goals based on the GRNN model and the NSGA-III multi-objective optimization algorithm.This thesis firstly sets the value range of the parameters to be optimized through enterprise research,and then obtains the simulation data of multiple sets of working conditions based on the numerical simulation model as the data set of the data model,takes the parameters to be optimized as the model input,and uses the energy efficiency and quality indicators as the model.The data model of the cement rotary kiln was constructed based on the GRNN algorithm,and then optimized based on the NSGA-III algorithm,so as to obtain the process parameter combination of the optimal operating condition,and finally compared the optimization effect of the optimal operating condition and the basic operating condition.The results of numerical simulation show that after optimization,the maximum firing temperature of the research object is increased by 183.1k,the length of the firing zone is increased by 10.8m,and the thermal efficiency is increased by 13.13%.It shows that this research method is effective in optimizing the energy efficiency and quality of cement rotary kiln,and can play a guiding role in cement production.